Research Investigação

Nematic and cholesteric droplets adsorbed on (structured) fibers: Statics and Dynamics

Wetting by a nematic liquid crystal for different substrates.

Wetting by a nematic liquid crystal for different substrates.

There are interesting questions to be asked about the way in which nematic droplets inter­act with surfaces. For example, the response of nematic liquid crystal drops of toroidal topology threaded in cellulosic fibers, suspended in air, at dif­fer­ent temperatures, and to an AC field at room tem­per­a­ture has been reported. The director is anchored tangentially at the fiber surface and homeotropically at the air interface. Upon application of the electric field, E, the disclination ring expands and moves along the fiber main axis, followed by the appearance of a stable rotating soliton-like “particle”. Necklaces of these liquid crystal drops open new perspectives for application in microelectronics and photonics.

Based on our experience on the statics (3D FEM to minimize the Landau-de Gennes free energy) and dynamics (3D Lattice Boltzmann Methods to solve the Beris-Edwards equations) of nematics and cholesterics (ongoing FCT projects), we aim to describe theoretically the equilibrium structures and the dynamical response to applied electric fields, in particular the rotating soliton-like “particle”.